[Twisted-Python] delay when sending data over SSH

Hi Everybody,
When I use
channel.SSHChannel.self.conn.sendRequest
from my client application it takes between 10-20 seconds until the
server (which runs on the same machine) gets it!
Does anybody has an idea, what's the problem?
When I open a new channel, channel.SSHChannel.channelOpen responds
directly. I do the sendRequest after I opened the channel.
Thanks alot
Tobias